Determination of carbethopendecinium bromide in eye drops by capillary electrophoresis with capacitively coupled contactless conductivity detection
Abstract
Septonex was determined by capillary electrophoresis with capacitively coupled contactless conductivity detection. Optimal separation was achieved in BGE of pH 7.0 containing 30mM 2-(N-morpholino) ethanesulfonic acid, 12.5 mg/mL of 2-hydroxypropyl-beta-cyclodextrin and 20% v/v of acetonitrile.
The separation was performed at 25 degrees C in an uncoated fused silica capillary (50 mm id; total length, 60.5 cm; effective length, 50 cm) at 30 kV. Samples were injected hydrodynamically at 50 mbar for 6 s.
For quantitative analysis, L-arginine (500 mu g/mL) was used as internal standard. The LOD was 7 mu g/mL of septonex (at S/N = 3).
The run-to-run repeatability (n = 6) was characterized by the RSDs of 0.18% for the migration time and 1.96% for the analyte/internal standard peak area ratio. Accuracy tested by recovery experiments at three concentration levels gave recoveries of 100.27-104.22% with RSD <= 2.19%.
The method was applied to the assay of carbethopendecinium bromide in eye drops.